Issue 19

G. Bolzon et alii, Frattura ed Integrità Strutturale, 19 (2012) 20-28; DOI: 10.3221/IGF-ESIS.19.02

1.5

C1 C2 C3 C4

1.0

0.5

Separation Force [N]

0.0

0

5

10

15

Separation Distance [mm]

Figure 11: Graphical representation of the identified traction − separation law in the four cases shown in Tab. I (left) and the reconstructed load − displacement curves compared with the experimental output (right); output C2 corresponds to the best matching solution (see Tab. 1).

[N]

[N]

[N]

[mm]

[mm]

ω opt

F max

F 1

F plat

D 1

D 2

Initialization Converged

0.6

0.54

0.2

1.1

5.5

22.35

1.151 7.023 Table 2 : Initialization vector and parameter values returned by the minimization of the discrepancy function ω based on the crack opening profile only. 1.043 0.250 1.445

Figure 12: Graphical representation of the experimental output compared with the load − displacement curve reconstructed by the parameter values listed in Tab. 2.

C LOSING REMARKS AND FUTURE PROSPECTS

he combination of properly designed experiments and of the numerical simulation of even complex laboratory tests constitutes the basis of inverse analysis procedures, which are widely exploited to material characterization purposes also in fracture mechanics context. In the presented application, a large amount of information has been collected by means of digital image correlation techniques during non-conventional experiments carried out on heterogeneous material samples. Information concerning crack opening profiles has been extracted and used to calibrate the parameters entering a suitably defined interface model, demonstrating the significant informative content of these deformation data. T

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